With the development of an electronic technology and communication network, various devices and methods enabling communication between users are being developed. Thus, users may perform communication by using various methods such as a wireless phone, internet phone, video communication as well as a corded phone.
In particular, a communication technology using a wireless communication technology enables communication with the opposite side any time irrespective of a time or place. Due to such convenience, mobile communication devices are currently possessed by most people.
A 4th generation (4G) mobile communication technology enabling high-speed data transmission has also been recently developed succeeding 1st Generation (1G) mobile communication technology enabling only voice calls, 2nd Generation (2G) and 3rd Generation (3G) mobile communication technologies. In the case of a voice call, a 3G mobile communication service, such as wideband code division multiple access (WCDMA), compresses a voice signal by using an adaptive multirate-narrowband (AMR-NB) mode but recently, an adaptive multirate-wideband (AMR-WB) compression mode has been developed which is capable of providing a high-quality audio service such as a voice over LTE (VoLTE) service and providing a wider frequency band and high-quality sound as compared to the AMR-NB.
A mobile communication device is being recently manufactured to be capable of use both an AMR-NB mode and AMR-WB mode for a voice call service. Thus, while a voice call is performed by using a 3G mobile communication service, there may be cases where an AMR-NB mode service is switched to an AMR-WB mode service or vice versa for some reasons such as a network situation or handover. When a compression mode varies during the voice call, a user experiences a sudden change in sound quality and thus there may be a limitation in that a commitment to the call decreases.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.